Dino ignition problem

What plugs are you running?

On the overhaul did you change to high comp pistons.

Have you checked the leads? disy cap?

Black sooty plugs are a good indication you are rich, when you tighten up the thottle linkages do you check the airflow. Any increase when you re-tighten the linkages can have the front carbs drawing to much air.

Are the idle jets clean?

 

Slightly confused as to why the front bank gets the problem with sooty plugs and the rear bank is clean!!

It seems that the problem is common to the front bank and the thing that can be wrong is the carb set up. Odd that all three cyl's are affected, if it is ignition problem then it must be something that is common to the front bank. But why does it do it a low revs? Try swapping the rear plugs with the front ones and see what happens.

If the front set foul up and the rears are cleaned then it narrows down the search.

Could be the MSd controller, not familar with that one i am afraid. Is the coil OK.

Just purchased a new prog ignition system and kept getting misfiring at low revs, when i floored it, she shot up the road like a scalded cat. Cruised at 40mph, misfired.

Checked the coil and found she was running too hot (i mean really hot). Changed the coil as i thought it may be breaking down under load. Cured it

Is this MSD programmable?

The reason i asked about the plugs is that i used BP8 and got fouled plugs after an unleaded conversion, swapped to BP7 and they were OK.

 

Can't you rule out the coil since there is only one and common to all cylinders?

Just a wild thought, but doesn't the crankcase venting/EGR valve empty into the front bank somewhere?

 

Get an Expert to adjust the carbs !
Sometimes driving them with new sparkplugs helps.

 

Should be able to rule out ignition with your setup. I prefer to set carbs with air bypass screws as much in as possible but that should be a small problem. There might be a clue in the idea of oil vapor blowing back into the near carbs but with a new engine, that does not seem reasonable. Easy to test though, just remove the airbox cover and run for 20-30 miles and see what the plugs look like then. Let us know what you find. Thanks, John

 

Choke cable runs through each 3-cylinder bank as a unit. Could the choke cable be bound on the one side? If you have the choke cable connected, make sure that all of the choke levers are free to return to their stop!!!!

This will lead to exactly your symptom...!

Jim S.

 

Gary - Are the fouled plugs causing the misfire ? How have you arrived at that, or is it something else in the ignition + carbs. The fouled plugs could be a red herring.

I would suggest you turn out the air bypass screws 1.5 turns. Have you had a problem before with them at that setting, doubt it. It gives all the carbs a starting point for finer adjustment.

 

Looking at things in logical order, what affects the front and rear barrels. Each carb feeds cylinders 1-4,2-5,3-6. As the problems is the front bank, the common denominator is a few things.

Gary

Incorrectly adjusted bypass screws will normally cause a lean condition, snapping or popping thru the carbs. This is because too much air is diluting the mixture control setting. Setting to 1.5 turns of bottom is a starting point, the unisym is then used to balance out the airflow. Be careful though as too high idle speed setting lifts the butterflies above the progession ports, which will allow fuel to be drawn in thus causing and overich mixture. Also this can lift the accelrator pump circuit and cause droplets to splash onto the butterflies too. Having said that you would expect the problem to show on the opposite bank of cylinders. ie badly adjusted idle would affect
1-4,2-5 or 3-6.

So the problem could be a vaccum leak on the inlet manifold O rings, gaskets, you would get a popping back thru the carb/s, misfiring during acceleration, engine hunting at high speed, snapping back through the exhaust at deceleration. Yet again it has been known to have a badly fitting manifold?? Does the mixture screw adjustment to these banks have a noticibable effect? If they are slow to respond then it points to vac leak, plug spark u/s or plugged idle jets.

Yet again the symptoms you describe relate to something common to the front bank, what?

Can you tell me what happens if you fit fresh plugs and take it out for a good blast down the road. Does it misfire straight away ? What colour are the plugs on all cylinders. choclate brown is ideal.

Are you sure the misfire relates to the fouled plugs? With all three plugs fouled up, how does it start!!!!

Tony

 

It only costs 200 euros for an expert to set up and check carbs here in Italy,their is alot of people that use tools and stuff to set up.But my carb Ferrari was set up by a Professional and since the 2 years he set it up by ear(no instruments) the car beats the hell out of 348s,its perfect.

Its easy for an inbalance and I seen modern mechanics which don't know nothing about carb adjustment.An expert with new Ferraris could not adjust my carbs,then I took it to the professional.
The professional balances the countach carbs by ear,and thats brilliance!

Why go insane and just get a carb guy to adjust them and your on the go!

Or does it cost thousands to do this job in the U.S?

 

Carbs go better than injection cars look at the 308 carb and the 308 i.Also carb BB and BBi.


Once I had problems with the sparkplug extensions which were dissipating electricity and not making the sparkplug have the correct spark ,it made a problem similar to yours.
I changed sparkplug extenders and sparkplugs and the car was going good again.

 

Gary

Just a thought, do you have the US disy with 6 lobe (single points) or the Euro 3 lobe ( 2points).

If you have the 3 lobe with dual points, is one set out of phase or moved?

I THINK i am correct in stating the one set does, 1,2,3 cylinders and the second set does 4,5,6 (hence the 1,4,2,5,3,6 firing order)

Worth a look if you haven't already tried it!!

It would certainly explain one bank misfiring

Cheers

Tony

 

As far as i am aware they are not available anymore. Contact Ron at Superformance UK he may be able to help you.?

Tony

 

Bought the kit from Superformance.co.uk about 2 years ago. Fit and finish were bad and pins were not hardened. Cleaned up weights and used old hardened pins. Springs were fine and weights had right ballance. Adjusted diameter of phenolic inner stop tube on rotor shaft and played with washers behind springs. Was able to match published advance curve. Lubed everything and put back together. Been flawless for 2 years and 9,000+ miles. Have checked advance on car a couple of times. Always smooth to the right rpms. I just checked the Superformance site and the kit is now machine cut with hardened pins. Should be a good source.
John